Vulnerability Database

374,078

Total vulnerabilities in the database

CVE-2025-39768 — linux / linux_kernel

Reachable Assertion

In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: HWS, fix complex rules rehash error flow

Moving rules from matcher to matcher should not fail. However, if it does fail due to various reasons, the error flow should allow the kernel to continue functioning (albeit with broken steering rules) instead of going into series of soft lock-ups or some other problematic behaviour.

Similar to the simple rules, complex rules rehash logic suffers from the same problems. This patch fixes the error flow for moving complex rules:

  • If new rule creation fails before it was even enqeued, do not poll for completion
  • If TIMEOUT happened while moving the rule, no point trying to poll for completions for other rules. Something is broken, completion won't come, just abort the rehash sequence.
  • If some other completion with error received, don't give up. Continue handling rest of the rules to minimize the damage.
  • Make sure that the first error code that was received will be actually returned to the caller instead of replacing it with the generic error code.

All the aforementioned issues stem from the same bad error flow, so no point fixing them one by one and leaving partially broken code - fixing them in one patch.

  • Published: Sep 11, 2025
  • Updated: Nov 26, 2025
  • CVE: CVE-2025-39768
  • Severity: Medium
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: Medium
  • Score: 5.5
  • AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CWEs:

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.